ACTA1 and chronic kidney disease: Recently, in a study [52] of renal biopsy samples from patients with progressive CKD, coexpression of macrophage markers (F4/80 and CD68) and a fibrotic marker (α-SMA) in conjunction with the accumulation of collagen I were found in the renal interstitium, suggesting that macrophage-to-myofibroblast transition (MMT) may be another pathway that contributes to renal fibrosis in CKD.